AutoCodes – GMC – P119A 2014 GMC Sierra

P119A 2014 GMC Sierra Code - NOx Sensor 1 Signal Circuit

Quick Answer

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P119A 2014 GMC Sierra indicates NOx Sensor 1 Signal Circuit.
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 147

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P119A 2014 GMC Sierra Description

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. There are two NOx sensors, one placed upstream of selective catalytic reduction, to measure inlet NOx concentration, and one placed downstream. They are connected with the control module via CAN and all the information is exchanged through it. Since it is a smart sensor, all the electrical monitoring is performed inside the sensor and only the results are sent to the Engine Control Module (ECM). Each NOx sensor contains a sensing cell, a pumping cell, and a heater. A sample of exhaust gas passes through a diffusion gap between the sensing cell and the pumping cell. The NOx sensor maintains a constant reference voltage across the sensing cell. An electronic circuit within the sensor controls the pump current through the pumping cell in order to maintain a constant voltage in the sensing cell. The amount of current required to maintain the reference voltage in the sensing cell is proportional to the concentration of NOx in the exhaust. The ECM varies the amount of diesel exhaust fluid (reductant) added by varying the reductant injector duty cycle in response to changes in engine exhaust NOx levels. The smart NOx sensors consist of two components, the NOx module and the NOx sensor element that are serviced as a unit. A circuit or performance condition with a NOx sensor is detected by the NOx sensor module. The smart NOx sensor module communicates the condition to the ECM over the serial data line. The ECM sets a DTC when a serial data message is received from the NOx sensor module. The Diagnostic Trouble Code (DTC) will be set if the ECM software detects a fault in the NOx sensor circuitry or a performance fault in the NOx sensor for greater than 2 s.

OBDII Code P119A 2014 GMC Sierra - NOx Sensor 1 Signal Circuit - AutoCodes.com — P119A 2014 GMC Sierra Code - NOx Sensor 1 Signal Circuit

What does this mean?

What are the Possible Causes of the DTC P119A 2014 GMC Sierra?

Faulty Nitrogen Oxides (NOx) Sensor
Nitrogen Oxides Sensor harness is open or shorted
Nitrogen Oxides Sensor circuit poor electrical connection

How to Fix the DTC P119A 2014 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P119A 2014 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P119A 2014 GMC Sierra code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P119A 2014 GMC Sierra Code

1. What does the OBDII code P119A mean for a 2014 GMC Sierra?

P119A indicates an issue with the NOx Sensor 1 Signal Circuit, which monitors nitrogen oxide levels in the exhaust system to ensure proper emissions control.

2. What are the common symptoms of code P119A?

Symptoms may include the check engine light turning on, reduced engine performance, increased fuel consumption, and potential failure to pass emissions testing.

3. What causes code P119A to appear on a 2014 GMC Sierra?

Common causes include a faulty NOx sensor, damaged wiring or connectors in the sensor circuit, exhaust system leaks, or issues with the vehicleâ€™s engine control module (ECM).

4. Can a bad NOx sensor cause drivability issues?

Yes, a malfunctioning NOx sensor can lead to reduced engine efficiency, poor fuel economy, and sluggish acceleration due to incorrect air-fuel mixture adjustments.

5. How do you diagnose code P119A?

Diagnosis typically involves scanning the vehicle for codes, inspecting the NOx sensor and its wiring for damage, checking the sensor's signal output, and testing for exhaust leaks.

6. Is it safe to drive with the P119A code active?

While the vehicle may still be drivable, operating it with this code active could lead to further damage to the emissions system and reduced engine performance over time.

7. How much does it cost to repair code P119A on a 2014 GMC Sierra?

Repair costs can vary depending on the issue, but replacing the NOx sensor typically costs between $200 and $600, including parts and labor.

8. Can I fix code P119A myself?

If you have automotive repair experience, you may be able to replace the NOx sensor or repair damaged wiring. For more complex issues or ECM problems, professional assistance is recommended.

9. Does the P119A code require reprogramming the ECM?

In some cases, after replacing the NOx sensor or repairing the circuit, the ECM may need to be recalibrated or updated to ensure proper functionality.

10. What happens if the P119A code is ignored?

Ignoring the code can lead to increased emissions, reduced fuel efficiency, potential damage to the catalytic converter, and failure to meet regulatory emissions standards.